A gate driver on array (GOA) circuit for driving pixel circuit is usually used for replacing an external chip in the display technique field. The GOA circuit is manufactured by forming gate driver ICs on the pixel substrate (also known as array substrate) by using array substrate process. Because the external chip is replaced by the GOA circuit, the number of procedure in manufacturing display apparatus and the manufacturing cost are reduced. At the same time, because the GOA circuit is to manufacture the gate driver ICs on the array substrate, the integration of the display apparatus is increased.
The GOA circuit is formed by connecting a plurality of GOA circuitry unit in cascade, and each of the GOA circuitry unit drives at least one pixel line on the array substrate for displaying. The GOA circuitry unit provides two kinds of signals:
(1) scan signal (SCAN), for turning on the thin film transistors (TFT's) connecting to the pixel line in a time period so that scanned data signals can be input to the capacitors in the circuits of the pixel line, and turning off the TFT's in other time periods so that the capacitors are not affected by scanning the data lines thereafter. The scan signals further initialize the potentials of the capacitors before inputting the scanned data signals to the capacitors or initialize anodes of the organic light-emitting diodes (OLED's).
(2) emission signal (EM), for driving some TFT's when the scan signal turns on the TFT's connecting to the pixel line, so that the OLED's are prevented from emitting light when inputting the scanned data signals or initializing to allow to input the scanned data signals accurately.
Therefore, the GOA circuitry unit generally comprises two independent parts, i.e., SCAN circuitry part and EM circuitry part. The SCAN circuitry part provides SCAN signals, and the EM circuitry part provides EM signals. Each circuitry part comprises TFT's and capacitors of itself. Accordingly, the whole GOA circuitry unit and the cascaded GOA circuit comprise more and more TFT's and capacitors and are harmful for narrow border design of the display device because the GOA circuit is usually designed to be arranged at boundary of the array substrate of the display device. At the same time, the independent two circuitry parts result in output phase mismatching.